Substantial posts by B.D.R., who started the thread, and by the forum’s most active contributors. 70 of 109 posts are listed.
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B.D.R., 9 September 2007NEW THREAD (ACOUSTIC FORUM) http://www.johnlsayers.com/phpBB2/viewtopic.php?t=10467 MEASUREMENTS & CORNERS EXPERIMENTS, HERE FROM PAGE 2 TO PAGE 7 Hello. I have a…
gullfo, 9 September 2007there's not a lot of space :-) you probably have the right placement for instruments. i'd add corner trapping - including wall-ceiling corners. i'd also build a drum…
B.D.R., 18 September 2007Thank you Kendale! So... there is a concrete step in the floor...I will build two risers, one for the right leg and pedals of the piano , and one for the drum set ,…
kendale, 19 September 2007Aloha, Ahem! Watch that pic size :wink: Moving forward... How high is that step? It would seem to be somewhat of a safety hazard to have to negotiate. Is it possible to…
B.D.R., 19 September 2007Thank you Jerry, yes, it helps! The step its about 3 3/4" high. I can make that high with two 2x4 studs plus a 3/4" plywood.. please take a look of the picture below, I…
B.D.R., 20 September 2007Here an experiment for the drum riser, 8 pound mineral wool in the floor next to the step...then plywood on top..."not in the picture" this really resonate like a deep…
B.D.R., 20 September 2007thanks for your help gullfo, Sorry Gulfo and Kendale, I just realized that I don't need a drum riser :oops: ... I just need a small riser for the drummer chair similar…
B.D.R., 26 September 2007Kendale, thanks for the layout , I experimented with it...but the drum doesn't sound really good in that corner there...and the piano sound better if toward the center…
gullfo, 27 September 2007it depends on the room modes. we can estimate based on the size what frequencies are most problematic, or you could measure the room (using Room EQ wizard or ETF for…
B.D.R., 29 September 2007Thanks Glenn, about the room testing... I have NOT experiences in room testing, and I guess it can be very tricky.. I will be using home hobbyist equipment like radio…
B.D.R., 26 October 2007Thank you Glenn, finally I can make measurement's , I'm using room EQ wizard and behringer measurement mic, also I'm using the spl meter for calibration. "behringer…
gullfo, 27 October 2007you want to look at the low frequency decay and waterfall, to determine what room modes you have. in general you'll want broadband bass trapping in the room but you'll…
B.D.R., 29 October 2007ROOM MEASUREMENTS STARTS FROM HERE Thanks Glenn, I made all the measurements today... but the original files are about 3 Mb each, too big to post , I will post some JPG…
B.D.R., 29 October 2007more Image not preserved: center of short wall ceiling corner.jpg Image not preserved: center of long wall ceiling corner.jpg Image not preserved: ceiling 3corner mic…
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B.D.R., 6 November 2007CORNERS BASS TRAPS MEASUREMENTS STARTS FROM HERE Low frequencies measurements I made the following measurements with the sub woofer in the floor tri-corner and the mic…
B.D.R., 9 November 2007Thanks Glenn, Here more measurements sub woofer and speaker in the floor tri-corner, mic on listening position. 4 different kind of acoustic materials floor to ceiling…
B.D.R., 10 November 2007here 3 different measurements, Yellow line: (20) Aur. Lenrds Blue line: same (20) lenrds with additional (6) 8 pound mineral wool panels in front of the lenrds, floor to…
B.D.R., 10 November 2007here more, 8 , Lenrds in the room, two in each corner (blue line) 4 , 2x4x4" 8 pound mineral wool panels , one in each corner (red Line) Combination , 8 Lenrds two in…
B.D.R., 10 November 2007here one more (Pink line) 20 Lenrds, I made a gigantic mega Lenrd foam bass trap made by 12 Lenrd all together in the floor tri-corner where the drum is... there is…
B.D.R., 12 November 2007CORNER BASS TRAPS MEASUREMENTS WITH PICTURES STARTS FROM HERE Thanks Glenn, here all the new measurements and pictures.. sub and speaker still in the corner , for…
B.D.R., 12 November 2007... Image not preserved: gigantic floor lenrd.JPG Image not preserved: gigantic lenrd plus 3 regular lenrds , corner floor to ceili.jpg Image not preserved: IM004390.JPG…
B.D.R., 12 November 2007... Image not preserved: corner cylinder, floor to ceiling.jpg Image not preserved: 2.5 pounds absorber 6x4x4inc.JPG Image not preserved: 2.5 pound 4 inc tick 4x6 corner…
B.D.R., 12 November 2007Ceilings Tile... Image not preserved: 1 l. ceilings tile.JPG Image not preserved: 1 layer of ceilings tile 2 feet wide floor to ceiling.jpg Image not preserved: ceiling…
B.D.R., 12 November 20078 pound with FSK Foil toward the room, toward the corner etc . Image not preserved: 8 pounds 2 inc tick (fsk) corner absorber floor to ceiling.jpg Image not preserved: 8…
B.D.R., 13 November 2007Thank you very much msikio that look very interesting, and also simple to build... I agree plywood vibrate! I can feel it with my hand wile I play the bass drum!! My sub…
B.D.R., 15 November 2007thank you Jeff, I'm done with step 1 and measurements already. 4.09 am, ... I stacked Lenrds and mineral fiber on all 4 corners, floor to ceiling 16 lenrd and 8 , 2x4x4"…
B.D.R., 15 November 2007.. Image not preserved: for jeff, room with 4 lenrds in each corner (red line).jpg Image not preserved: for jeff, 4 lenrds in each corner waterfall 20 to 180 hz.jpg…
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B.D.R., 15 November 2007.. Image not preserved: for jeff , lenrds plus 8 pound , waterfall 180 to 340 hz.jpg Image not preserved: for jeff lenrds plus 8 pound combination, 340 to 497hz…
lovecow, 15 November 2007This is great information, Gab. I'd like to provide a quick technical perspective on this. For the sake of brevity, I'm going to focus on two of your modal problems, at…
B.D.R., 15 November 2007thanks for the energy Jeff, last night was too late for playing drums (axially morning 4.00 am) so I had to wait until now.. Yes, sound tighter, I can hear the…
B.D.R., 16 November 2007OK /I will add some diffusers over the instruments and few more starting from the center of the two short walls where long flutter echos.. but...what about bass…
lovecow, 16 November 2007Gab, A few thoughts on that: 1. I did not address your "linear T 60 " inquiry above. To that end, I do not subscribe to this school of thought. A small rise in low…
B.D.R., 18 November 2007thanks Jeff! Done ! here some pictures and measurements I didn't place anything permanently.. so I'm not worry about how it looks.... my first impressions... (but I need…
B.D.R., 18 November 2007And here all the measurements Image not preserved: all measured drum overhead mic position diffusion and and corner traps.jpg Image not preserved: all measured with 1.3…
B.D.R., 18 November 2007Impulse response and low frequency decay Image not preserved: impulse response, bass traps and diffusion in the room.jpg Image not preserved: l f decay, 2 to 240 hz,…
lovecow, 18 November 2007I think you might be ready to just "tweak" the room. From the above comment, I would guess that you probably need to swap out some wall diffusers for some absorption.…
B.D.R., 18 November 2007thanks misikio, I'm writhing some questions for Jeff and yes I do want to try john slat but I don't know how to tune them and how many etc I'm building a corner poly in…
B.D.R., 18 November 2007Thanks Jeff, please, before you leave me alone for ever.. :) I never understood "you said...beyond the point of measurements" the point... Too much high frequencies…
lovecow, 19 November 2007Gab, "Analysis paralysis." At some point, the measurements won't be useful - to us - anymore... ...because we have nothing to correlate the measurement to... ...we are…
B.D.R., 19 November 2007thank you for answering to all my questions Jeff. hopefully :) ... OK, on the walls, will be better to use 2'x2' diffusers varying the axis/position of each diffuser…
lovecow, 19 November 2007It wouldn't appear to me that this will make much difference. Could be a good thing since it will give you more versatility. I did see that and it's useful, at least for…
B.D.R., 19 November 2007thanks misikio, I'm using the room eq wizard suggested by Gulfo right now, I hope there is a way/ option to calculate the RT60 with the program I already have.. About…
B.D.R., 19 November 2007Ok Glenn thanks but, :? I made all this measurements because you said...: To be honest I don't really know what frequencies are most problematic, all the measurement…
gullfo, 19 November 2007two things to look for: one - room modes which are the large dips or peaks in the response below 300hz. second - the high frequency reverberation times and/or echoes.…
B.D.R., 19 November 2007thanks for the overview Glenn And this is exactly my point, how I'm going to work those corners...? "I want to flatten this modes before they multiply... I don't…
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gullfo, 20 November 2007have you tried 4" thick 3pcf or 6pcf rigid fiberglass across the corner? a properly sealed poly floor to ceiling? something to trap a lot of air and acts on the velocity…
B.D.R., 20 November 2007Thank you Glenn, No, I never tried 3pcf or 6 pcf or a sealed poly, only foam, 8 pcf and 2.5pcf. and R insulation. The big poly made by a curved 4x8 1/4 plywood lined…
gullfo, 20 November 2007the poly is not as efficient as the heavy rigid fiberglass for a broad band absorption, but it does adds diffusion and trapping in one unit - at the cost of extra space.…
B.D.R., 20 November 2007Glenn thank you, OK about the single corner things... So...In your opinion will be enough if I treat all the 4 corners like in the example below with 2 regular 2x4 4"…
gullfo, 20 November 2007Hi Gab, you can see where the response is tightening by almost 10db in some cases, but you can also see that between 100hz and 200hz you're getting a lot of absorption.…
B.D.R., 20 November 2007thanks for explaining Glenn. Yes I guess the modes are annoying, Before building the panel traps I would like to try one more things.. (4) Mega Lenrd floor to ceiling in…
B.D.R., 21 November 2007Hi Jeff, I don't have mega lenrds, but I make the same size absorber with 4 Lenrds together ... I can make a wider megalenrd too if I need , see the pictures below P.S.…
B.D.R., 22 November 2007OK Glenn and also Jeff, thanks for helping me out with this, I think everything is clear for me now. 1) I can clearly hear during the sweep, big nulls and picks and…
B.D.R., 22 November 20072) Additional 4 inc tick 8 pound 2x4 absorbers in front o the Lenrds floor to ceiling , (16 lenrds plus 8 2x4x4" absorbers in the room) 1/3 octave smoothing and regular…
B.D.R., 22 November 20073) 4' wide 4" tick , 8 and 2.5 pound absorbers plus mega lenrds floor to ceiling ( 5 mega lenrds, 2 -4x8x4" absorbers, 1 4x6x4" absorber) 1/3 octave smoothing and…
B.D.R., 22 November 2007here the same 3 measurements all togheter, 1/3 octave smoothing and regular black = lenrds only blue = lenrds behind 8 pound absorbers red= large 4 feet wide absorbers…
B.D.R., 22 November 2007thanks misikio From studs to inside the room: Walls: Studs -5/8 screwed drywall - 5/8 glued ceiling tile - 5/8 glued drywall -paint. Ceiling: Studs- 5/8 screwed drywall…
B.D.R., 23 November 2007Thanks Jeff, No, I don't need treatment at 150hz specifically, I said that ? :o My last experiment was about using very large 8 pound and 2.5 pound 4'x8'x4" absorbers…
gullfo, 23 November 2007if the corner traps are too absorbant, you could try to put something like a diffuser over it to reflect the sound back into the space and still provide low end…
B.D.R., 24 November 2007thanks Glenn , 4 feet wide 4" tick, 8 pounds, 4x6 or floor to ceiling across corners works much better than the other options I experimented here...I can hear the…
B.D.R., 26 November 2007thanks Glenn, the link you send me it shows MEGA LENRDS compared with SUPER CHUNKS and CORNER ABSORBERS. There is no regular size LENRDS data on the examples... I can…
B.D.R., 27 November 2007thank you Glenn, look like, Ethan low bass trap is centered around 90 or 100 Hz, which is where porous traps straddling corners also peak What about the big corner Poly…
Eric_Desart, 27 November 2007B.D.R. You asked me to have a look here. But you're doing right with all your testing. And whatever it remains difficult to draw general conclusions, which isn't that…
gullfo, 27 November 2007as Eric points out, straddling the corner with panels or slats becomes an approximation since you can only average values to estimate the range of performance. since…
B.D.R., 28 November 2007Thanks for the encouragement. Too bad, they should make them bigger then, I paid for it... That's will be the simplest approach , but what about if you paid for it and…
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Eric_Desart, 28 November 2007B.D.R. If you want to do something about that, but it costs energy and whether it helps or not I don't know, is writing them a letter . If you do you can refer to my…
B.D.R., 28 November 2007Thank you very much Eric, this acoustic stuff it's difficult science...not to easy for a musician to understand . one more things... . Foam improve sound isolation? Is…
Eric_Desart, 28 November 2007B.D.R. In order to judge communication, between whoever, I should want to see the exact communication from both sides, in order to see everything in the right complete…
Eric_Desart, 28 November 2007Yes you could use True Panels inside your walls to increase isolation. But it should be completely senseless. The best absorption to put inside a wall is low density…
B.D.R., 28 November 2007Well, publishing the room analysis, at this point how much it's going to help any ways... I mess up with isolation already... and then spent over $1000.00 in foam,…